Kavod Harav,
Q. If one spoke after hearing Kiddush and before drinking the wine (before the cup was passed to him), he has to bless again. but if one spoke after hamotzi, after the baal habayis took a bite, he does not bless again. Why?

A. Horav Shlomo Miller Shlit’a pointed that Remoh (O.H. 167: 6) indeed rules that if one spoke and was mafsik or interrupted after listening to the brocho of the mevarech, but also after the mevarech ate from the bread, he does not have to repeat the brocho and the Remoh may maintain the same in regards to a break after the wine brocho. However, Mishna Berura (ibid. 43) mentions that almost all Poskim disagree with Remoh’s ruling and maintain that the one that spoke unnecessarily has to repeat hamotzi, similar to the one listening to kiddush that was mafsik before drinking fro the wine.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a